Ikelite strobe - does the job, but be careful buying used.
Ikelite strobe - does the job, we've been real happy using it to photograph shipwrecks in Lake Michigan at depths to 150 feet using dual strobes and a canon s90 in an ikelite housing for several years. But be careful buying used, if they fall from a table or something the sensor window can crack and cause leakage and it's hard to see the crack so it may look fine but still leak. So make sure the seller has a return policy or get it really cheap.